need help for IC st m27c512

Thread Starter

ArezDev

Joined Dec 16, 2019
16
my yamaha d2040 digital channel divider has been used about 3 years ago, and yesterday i can't used it again.

only what i got is just the logo. no more and can't boot to menu.

i was wondering if iam asking about IC st m27c512, if this IC has been broken or damaged. would it impact to the code?

i already copy a program code from older ic that have broken, i mind its maybe only damaged on this IC so I already bought a new one and copy that program to a new IC.

so what iam asking for is: when i copy from old ic, should it be compiled first or something??

Iam so new about programming IC, and dont know what i must do.
 

ericgibbs

Joined Jan 29, 2010
9,517
hi AD,
The 27C512 is a erasable EPROM, used to store the Program code.
If it is damaged it will cause problems.

Copying or Cloning a damaged EPROM will not fix the problem

In order to Compile for a new EPROM, you need the original Program Source Code.

E
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
hi AD,
The 27C512 is a erasable EPROM, used to store the Program code.
If it is damaged it will cause problems.

Copying or Cloning a damaged EPROM will not fix the problem

In order to Compile for a new EPROM, you need the original Program Source Code.

E
If i can, where to get that program source code?
 

LesJones

Joined Jan 8, 2017
2,492
If you have bought a programmed 27C512 with the EXACT version of code for your device I don't see why you need to program another another EPROM from it. If you copied the faulty eprom you will have the same corrupt code in the one that you programmed. If the sticky label had been removed from the window on the original eprom then long term exposure to visible light may have erased it. (They are normally erased in a few minutes with UV light.)

Les.
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
If you have bought a programmed 27C512 with the EXACT version of code for your device I don't see why you need to program another another EPROM from it. If you copied the faulty eprom you will have the same corrupt code in the one that you programmed. If the sticky label had been removed from the window on the original eprom then long term exposure to visible light may have erased it. (They are normally erased in a few minutes with UV light.)

Les.
how do i find? i already do some search on any search engine and not found who has sell the programs
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
hi AD,
The 27C512 is a erasable EPROM, used to store the Program code.
If it is damaged it will cause problems.

Copying or Cloning a damaged EPROM will not fix the problem

In order to Compile for a new EPROM, you need the original Program Source Code.

E
so it will impact the code or not?
 

RamaD

Joined Dec 4, 2009
328
If the original old IC is good with the program intact, then you can copy and use it. There is nothing else required. No compilation etc., are required.
But if the original is damaged, then the copy will also be damaged.
 

dl324

Joined Mar 30, 2015
9,962
i was wondering if iam asking about IC st m27c512, if this IC has been broken or damaged. would it impact to the code?
I assume the quartz window was covered. Even with the window covered, programmed bits will loose electrons over time. The stated retention period for EPROMs is around 10-20 years, though most datasheets seem to omit that information. The number of erase cycles supported is around a dozen IIRC.

One way you can retrieve good data from an EPROM that you suspect is no longer providing correct data is to read it with a lower VCC. An EPROM with a 10% supply tolerance will operate down to 4.5V, but the ST programming algorithm for calls for a program verification pass at VCC=4.2V and 6.0V. So you should be able to do a read at 4.2V and 5.0V and compare the data.
 

dendad

Joined Feb 20, 2016
3,315
Why do you think the EPROM is damaged?
If it is "damaged" in that the code is corrupt, reading it to program a new on will not help. That will just copy the damaged code over to the new one.
You need an "undamaged" one to start with, and if it is undamaged, look elsewhere for the fault.
Or buy a new machine if you cannot find a new EPROM.
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
Why do you think the EPROM is damaged?
If it is "damaged" in that the code is corrupt, reading it to program a new on will not help. That will just copy the damaged code over to the new one.
You need an "undamaged" one to start with, and if it is undamaged, look elsewhere for the fault.
Or buy a new machine if you cannot find a new EPROM.
Do you have any friends who has sell for it? I will pay for it
Help me guys
 

LesJones

Joined Jan 8, 2017
2,492
Members are only able to help you if you answer their questions. You even quoted the question but made to attempt to answer it.

Les.
 

dl324

Joined Mar 30, 2015
9,962
Do you have any friends who has sell for it? I will pay for it
Help me guys
Have you tried reading the EPROM at VCC=4.2V and comparing that to the data you get from reading at VCC=5V?

Margin is supposed to be checked at VCC=6V. When an EPROM passes program verification at that voltage, it should retain data for 10-20 years. If you read the data at low VCC soon enough, you can recover the marginal data.

Do you have an EPROM programmer that allows you to read the data at VCC=4.2V (or less)?
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
IMG_20191219_220201.jpg

Only show this logo, if anyone who have this machine and want to share they program code pls reply me. Iam promised will pay for it. Thanks
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
Have you tried reading the EPROM at VCC=4.2V and comparing that to the data you get from reading at VCC=5V?

Margin is supposed to be checked at VCC=6V. When an EPROM passes program verification at that voltage, it should retain data for 10-20 years. If you read the data at low VCC soon enough, you can recover the marginal data.

Do you have an EPROM programmer that allows you to read the data at VCC=4.2V (or less)?
I dont have programmer eprom to read the data. Iam so new about program code, only know a little bit.

The main reason at your reply, i dont understand what you are want to tell about. :( can you give me a simple answer?
 

dl324

Joined Mar 30, 2015
9,962
The main reason at your reply, i dont understand what you are want to tell about. :( can you give me a simple answer?
Data in EPROMs is stored as a charge (electrons) on a floating gate. Over time, those electrons will migrate. When enough of them migrate and the charge on the floating gate will no longer be high enough to be read as being programmed.

If you read the data from such an EPROM at low VCC, that will change the threshold voltage for determining whether a bit is programmed. If you read the data at 4.2V soon enough after data starts reading incorrectly, you can recover the correct data. You can then use this data to program another EPROM.

I have EPROM programmers that allow me to set any voltage I want for reading, programming, and blank verifying. Anyone with equipment capable of reading at low voltage can program one that might work. That's why I asked where you are located. If you're in the US, I can do this.
 

Thread Starter

ArezDev

Joined Dec 16, 2019
16
Have you tried reading the EPROM at VCC=4.2V and comparing that to the data you get from reading at VCC=5V?

Margin is supposed to be checked at VCC=6V. When an EPROM passes program verification at that voltage, it should retain data for 10-20 years. If you read the data at low VCC soon enough, you can recover the marginal data.

Do you have an EPROM programmer that allows you to read the data at VCC=4.2V (or less)?
IMG_20191219_222119.jpg

Maybe what you mean is this?
My EPROM program is just have 3.30V, 4.00V, 4.50V, 5.00V, 5.50V, 6.50V.

at my program not showing for 4.2V
 

dl324

Joined Mar 30, 2015
9,962
Maybe what you mean is this?
Yes.
My EPROM program is just have 3.30V, 4.00V, 4.50V, 5.00V, 5.50V, 6.50V.

at my program not showing for 4.2V
Read the data at 5V, 4.5V, and 4V. Compare the data read at 4.5V and 5V. They should be different.

Then compare the data at 4V and 4.5V. If they're the same, you can use that data to program a new EPROM.

If the second compare isn't the same, you need to determine which bits are different to see if the cause might be VCC being too low. You could have an EPROM that won't operate at VCC=4V. STM only guarantees to 4.2V (implicitly from their programming algorithm).

This is the programming algorithm for M27C512:
clipimage.jpg

Also note that your program can't set the correct programming voltage. STM calls for VCC=6.25V. You might be able to use 6.5V. I never tried because I can set VCC to 6.25V for programming.
 
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